cocos2dx的图片加载

//data: 图片文件数据  dataLen: 文件长度
bool Image::initWithImageData(const unsigned char * data, ssize_t dataLen)
{
    bool ret = false;

    do
    {
        CC_BREAK_IF(! data || dataLen <= 0);

        unsigned char* unpackedData = nullptr;
        ssize_t unpackedLen = 0;

        //解紧缩pvr.ccz格局的图片
        //detecgt and unzip the compress file
        if (ZipUtils::isCCZBuffer(data, dataLen))
        {
            unpackedLen = ZipUtils::inflateCCZBuffer(data, dataLen, &unpackedData);
        }
        //解紧缩pvr.gz格局的图片
        else if (ZipUtils::isGZipBuffer(data, dataLen))
        {
            unpackedLen = ZipUtils::inflateMemory(const_cast<unsigned char*>(data), dataLen, &unpackedData);
        }
        else
        {
            unpackedData = const_cast<unsigned char*>(data);
            unpackedLen = dataLen;
        }
        //辨认文件类型
        _fileType = detectFormat(unpackedData, unpackedLen);

        switch (_fileType)
        {
        case Format::PNG:
            ret = initWithPngData(unpackedData, unpackedLen);
            break;
        ...
        //后面就是依据文件类型来进行图片解码初始化
        } while (0);

    return ret;
}
//data: 图片文件数据  dataLen: 文件长度
bool Image::initWit